We design, implement, and deploy more than 1,700 virtual machines over 40 sites for an on-site programming exam service, called CPE (collegiate programming exam), served by 16 servers, also hosted by virtual machines. The CPE is an on-site, with test administrations, isolated network, and closed book programming exam, conducted quarterly each year since 2010. It is to provide the certification of a student's programming skill, as a replacement of "skilled in C, C , Java" not easy to be verified descriptions in the résumé. Compared with conventional programming skill record, the CPE is a scaleable (serving